Table 1.

Assessment of the quality of the included articles

Section	Assessment item	Dick [19] (2012)	Talbot [23] (2000)	Çam [18] (2001)	Sarmiento et al. [22] (2004)	Kizilci et al. [4] (2012)	Heydari et al. [20] (2014)	Mohammad et al. [21] (2014)	Batista et al. [17] (2016)	Aquino et al. [3] (2018)	Wu et al. [5] (2021)	Xu et al. [9] (2021)
Introduction	Clear aims	+	+	+	+	+	+	+	+	+	+	+
	Appropriate design	+	+	+	+	+	+	+	+	+	+	+
Methods	Sample size justified	+	+	+	+	+	+	+	+	+	+	+
	Population defined	+	+	+	+	+	+	+	+	+	+	+
	Sample representative of population	+	+	+	+	+	+	+	+	+	+	+
	Selection process representative	-	+	-	+	-	+	+	-	+	+	+
	Measures to address non-responders	-	-	-	-	-	-	-	-	-	-	-
	Appropriate outcome variables	+	+	+	+	+	+	+	+	+	+	+
	Valid measures	+	+	+	+	+	+	+	+	+	+	+
	Defined statistical significance	+	+	+	+	+	+	+	+	+	+	+
	Methods described	+	+	+	+	+	+	+	+	+	+	+
Results	Results data described	+	+	+	+	+	+	+	+	+	+	+
	Concerns about non-response bias	-	-	-	-	-	-	-	-	-	-	-
	Non-responder information described	-	-	-	-	-	-	-	-	-	-	-
	Results internally consistent	+	+	+	+	+	+	+	+	+	+	+
	Results presented for analyses	+	+	+	+	+	+	+	+	+	+	+
Discussion	Conclusions justified	+	+	+	+	+	+	+	+	+	+	+
	Limitations identified	-	+	-	+	-	+	+	+	+	+	+
Others	Funding sources or conflicts of interests	-	-	-	+	-	-	-	-	+	+	+
	Ethical approval/consent obtained	-	-	+	+	+	-	+	+	+	+	+

+: Presence of the assessment item.